Since Sam's hear beats 220 times in 4 minutes, the proportion would be:
[tex]220\text{ to 4 =}220\colon4=\frac{220}{4}=\frac{110}{2}=\frac{55}{1}[/tex]next, to find the heart rate, we can set up the following proporitons:
[tex]\begin{gathered} \frac{220}{4}=\frac{x}{1} \\ \Rightarrow x=\frac{220}{4}=55 \\ x=55 \end{gathered}[/tex]therefore, Sam's heart rate is 55 beats per 1 minute
